JP2006021144A

JP2006021144A - Catalyst for cleaning exhaust gas and preparing method therefor

Info

Publication number: JP2006021144A
Application number: JP2004202135A
Authority: JP
Inventors: Hiroto Kikuchi; 博人菊地; Masaki Nakamura; 雅紀中村; Toru Sekiba; 徹関場; Katsuo Suga; 克雄菅
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2004-07-08
Filing date: 2004-07-08
Publication date: 2006-01-26

Abstract

<P>PROBLEM TO BE SOLVED: To produce a catalyst for cleaning exhaust gas, the high-temperature durability and catalytic activity of which are enhanced and to provide a method for preparing the catalyst for cleaning exhaust gas. <P>SOLUTION: The catalyst for cleaning exhaust gas contains a base material and a fine particle which is deposited on the base material, at least a part of whose surface is covered with a noble metal layer formed from one or more noble metals and the particle size of which is 5-100 nm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、自動車等の移動体に搭載されて、排ガス中の有害成分を浄化する排ガス浄化用触媒及びその調製方法に関する。 The present invention relates to an exhaust gas purifying catalyst that is mounted on a moving body such as an automobile and purifies harmful components in exhaust gas, and a method for preparing the same.

排ガス浄化用触媒の研究開発が従来から各種進められており、近年の自動車の排ガス規制強化に伴い、排ガス浄化用触媒の触媒性能を向上させることが望まれている。 Various researches and developments have been made on exhaust gas purifying catalysts, and it is desired to improve the catalyst performance of exhaust gas purifying catalysts in accordance with the recent tightening of exhaust gas regulations for automobiles.

排ガス浄化用触媒の触媒性能を向上させる対策の１つとして、基材表面に担持する貴金属を微粒子化する方法がある。貴金属を微粒子化すると貴金属粒子の表面積が大きくなり、排ガス中の有害成分との接触面積が拡大して排ガス浄化用触媒の性能が向上する。貴金属を微粒子化する方法として、逆ミセル法(マイクロエマルジョン)がある。 As one of the measures for improving the catalyst performance of the exhaust gas purifying catalyst, there is a method in which the noble metal supported on the substrate surface is made into fine particles. When the noble metal is atomized, the surface area of the noble metal particle is increased, the contact area with harmful components in the exhaust gas is expanded, and the performance of the exhaust gas purification catalyst is improved. There is a reverse micelle method (microemulsion) as a method for forming a noble metal into fine particles.

例えば、逆ミセル法を用いて貴金属を微粒子化すると同時に、貴金属よりも低価格である酸素吸蔵能等の効果がある金属を微粒子化し、貴金属微粒子と金属微粒子とを基材上に担持する方法が開示されている（例えば、特許文献１参照）。本方法によれば、逆ミセル法により貴金属又は金属を微粒子化した後、貴金属微粒子又は金属微粒子のいずれかを含浸法により担持するか、又は、貴金属微粒子及び金属微粒子の各々を還元又は水酸化物とした状態で互いに混合して基材に担持している。
特開２０００−４２４１１号公報 For example, there is a method in which a noble metal is made into fine particles using the reverse micelle method, and at the same time, a metal having an effect such as oxygen storage capacity, which is lower in price than the noble metal, is made into fine particles, and the noble metal fine particles and the metal fine particles are supported on the substrate. It is disclosed (for example, see Patent Document 1). According to this method, after the noble metal or metal is atomized by the reverse micelle method, either the noble metal fine particle or the metal fine particle is supported by the impregnation method, or each of the noble metal fine particle and the metal fine particle is reduced or hydroxide. In this state, they are mixed with each other and supported on the base material.
JP 2000-42411 A

しかしながら、前述した逆ミセル法により貴金属を微粒子化する製法では、粒径を正確に制御して貴金属を微粒子化できるという利点があるが、大量生産には不向きであり量産化することが難しかった。 However, the above-described production method in which the noble metal is made fine by the reverse micelle method has an advantage that the particle diameter can be accurately controlled to make the noble metal fine, but it is not suitable for mass production and difficult to mass-produce.

また、所謂含浸法によって基材に担持した貴金属粒子の初期粒径は、nm以下の超微粒子状態であるが、高温の酸化雰囲気下に排ガス浄化用触媒を晒すと、その表面が酸化されて、近傍の貴金属粒子と合体して数10nmに粗大化してしまう。特に、自動車等の移動体に搭載される排ガス浄化用触媒は、高温酸化雰囲気下に長期に亘り晒されるため、貴金属粒子の表面積の低下に伴い、排ガスの浄化率が低下してしまう恐れがあった。 In addition, the initial particle size of the noble metal particles supported on the base material by the so-called impregnation method is in an ultrafine particle state of nm or less, but when the exhaust gas purification catalyst is exposed to a high-temperature oxidizing atmosphere, the surface is oxidized, It coalesces with nearby noble metal particles and becomes coarse to several tens of nm. In particular, an exhaust gas purification catalyst mounted on a moving body such as an automobile is exposed to a high-temperature oxidizing atmosphere for a long period of time, so that the exhaust gas purification rate may decrease as the surface area of the noble metal particles decreases. It was.

本発明は、上記課題を解決するためになされたものであり、すなわち、本発明の排ガス浄化用触媒は、基材と、基材上に担持され、かつ、表面の少なくとも一部に一種以上の貴金属から形成される貴金属層を被覆すると共に、粒径が5nm〜100nmである微粒子と、を含むことを要旨とする。 The present invention has been made to solve the above-described problems. That is, the exhaust gas-purifying catalyst of the present invention is supported on a base material, the base material, and at least one part of the surface thereof. The gist is to cover a noble metal layer formed from a noble metal and include fine particles having a particle diameter of 5 nm to 100 nm.

本発明の排ガス浄化用触媒の調製方法は、無機化合物から形成される微粒子の表面の一部に、めっき法又は化合物分解法を用いて一種以上の貴金属から形成される貴金属層を被覆して触媒活性成分とする触媒活性成分調製工程と、触媒活性成分を基材上に担持する担持工程と、を含むことを要旨とする。 The method for preparing an exhaust gas purifying catalyst of the present invention is a catalyst in which a part of the surface of fine particles formed from an inorganic compound is coated with a noble metal layer formed from one or more kinds of noble metals using a plating method or a compound decomposition method. The gist is to include a catalytic active component preparation step as an active component and a supporting step of supporting the catalytic active component on a substrate.

本発明の排ガス浄化用触媒によれば、高温耐久性と共に触媒活性を高めることができる。 According to the exhaust gas purifying catalyst of the present invention, the catalyst activity can be enhanced together with the high temperature durability.

本発明の排ガス浄化用触媒の調製方法によれば、高温耐久性と共に触媒活性を高めた排ガス浄化用触媒を得ることができる。 According to the method for preparing an exhaust gas purifying catalyst of the present invention, it is possible to obtain an exhaust gas purifying catalyst having high temperature durability and enhanced catalytic activity.

以下、本発明の実施の形態に係る排ガス浄化用触媒及びその調整方法について、図１及び図２を用いて説明する。 Hereinafter, an exhaust gas purifying catalyst and an adjusting method thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

本発明の実施の形態に係る排ガス浄化用触媒は、基材上に微粒子を担持して構成される。微粒子の表面の少なくとも一部には、白金、パラジウム及びロジウムの中から選択される少なくとも一種以上の貴金属から形成される貴金属層を被覆しており、微粒子の粒径が5nm〜100nmである。なお、微粒子の粒径を5nm〜100nmと規定したが、微粒子が球状である場合に限定されるものではなく、微粒子が楕円形状である場合には、長軸方向における径が5nm〜100nmであることを意味する。 The exhaust gas purifying catalyst according to the embodiment of the present invention is configured by supporting fine particles on a base material. At least a part of the surface of the fine particle is coated with a noble metal layer formed of at least one kind of noble metal selected from platinum, palladium and rhodium, and the particle size of the fine particle is 5 nm to 100 nm. The particle diameter of the fine particles is defined as 5 nm to 100 nm, but is not limited to the case where the fine particles are spherical, and when the fine particles are elliptical, the diameter in the major axis direction is 5 nm to 100 nm. Means that.

このようにナノ単位である微粒子の表面の一部に貴金属から形成される貴金属層を被覆したため、貴金属層がシェル形状となり貴金属の比表面積が大きくなる。 As described above, since a part of the surface of the nano-sized fine particles is coated with the noble metal layer formed from the noble metal, the noble metal layer becomes a shell shape and the specific surface area of the noble metal is increased.

さらに、通常の含浸法を用いて貴金属を基材に担持した触媒に比べて、微粒子表面に貴金属層を被覆した触媒活性成分を触媒中に分散したため、貴金属粒子間の距離を大きくすることができる。この結果、高温酸化雰囲気下に排ガス浄化用触媒を長期に亘り晒した場合であっても、貴金属粒子のシンタリングを抑制でき、高温耐久性が高まる結果、排ガス浄化率の低下を防止することができる。さらに、微粒子の粒径を5nm〜100nmと規定したが、粒径が5nm未満になると、含浸法と何ら変わらず、高温耐久性が向上しないからである。一方、微粒子の粒径が100nmを超えると、γ−アルミナに貴金属を担持した従来の触媒と同様となり、貴金属粒子の分散性が低下するからである。 Furthermore, compared to a catalyst in which a noble metal is supported on a base material using a normal impregnation method, a catalytically active component having a fine particle surface coated with a noble metal layer is dispersed in the catalyst, so that the distance between the noble metal particles can be increased. . As a result, even when the exhaust gas purifying catalyst is exposed to a high temperature oxidizing atmosphere for a long period of time, sintering of the noble metal particles can be suppressed, and as a result, the high temperature durability can be increased. it can. Furthermore, although the particle diameter of the fine particles is specified to be 5 nm to 100 nm, if the particle diameter is less than 5 nm, it is not different from the impregnation method and the high temperature durability is not improved. On the other hand, when the particle size of the fine particles exceeds 100 nm, it becomes the same as the conventional catalyst in which the noble metal is supported on γ-alumina, and the dispersibility of the noble metal particles is lowered.

また、上記排ガス浄化用触媒において、貴金属層の厚さは、0.3nm〜3nmとすることが好ましい。このように本範囲に貴金属層の厚さを規定したが、厚さが0.3nm未満になると貴金属層を形成することができず、一方、厚さが3nmを超えると貴金属量が増えて高コスト化するからである。 In the exhaust gas purifying catalyst, the thickness of the noble metal layer is preferably 0.3 nm to 3 nm. In this range, the thickness of the noble metal layer is specified in this range.If the thickness is less than 0.3 nm, the noble metal layer cannot be formed.On the other hand, if the thickness exceeds 3 nm, the amount of noble metal increases and the cost increases. It is because it becomes.

さらに、上記排ガス浄化用触媒において、微粒子は、無機化合物から形成されることが好ましい。この理由は、微粒子を有機化合物から形成すると、微粒子が燃えてしまい貴金属層を形成することができないからである。また、無機化合物から微粒子を形成することにより、Pt等の貴金属の凝集を抑制することができる。より具体的には、微粒子は、アルミナ、セリア、ジルコニア、アルカリ金属及びアルカリ土類金属の中から選択される少なくとも一種以上の無機化合物から形成することが好ましい。また、微粒子は、アルミナ、酸化チタン、酸化鉄、酸化亜鉛、酸化セリウム、酸化イットリウム、酸化ケイ素、酸化マンガン、酸化マグネシウム、酸化ジルコニウム、酸化スズ、酸化銅、酸化コバルト、酸化タングステン、酸化モリブデン、チタンシリケート、アルミニウムシリケート、チタン酸バリウム及びこれらの複合化合物の中から選択される少なくとも一種以上の無機化合物から形成することが好ましい。 Furthermore, in the exhaust gas-purifying catalyst, the fine particles are preferably formed from an inorganic compound. This is because if the fine particles are formed from an organic compound, the fine particles burn and a noble metal layer cannot be formed. Moreover, aggregation of noble metals such as Pt can be suppressed by forming fine particles from an inorganic compound. More specifically, the fine particles are preferably formed from at least one inorganic compound selected from alumina, ceria, zirconia, alkali metal, and alkaline earth metal. Fine particles are alumina, titanium oxide, iron oxide, zinc oxide, cerium oxide, yttrium oxide, silicon oxide, manganese oxide, magnesium oxide, zirconium oxide, tin oxide, copper oxide, cobalt oxide, tungsten oxide, molybdenum oxide, titanium. It is preferably formed from at least one inorganic compound selected from silicate, aluminum silicate, barium titanate, and composite compounds thereof.

さらに、上記排ガス浄化用触媒において、貴金属層は、めっき法又は化合物分解法を用いて微粒子の少なくとも一部の表面に被覆して形成することが実用的であり好ましい。めっき法又は化合物分解法により貴金属層を形成すると、後述するように、貴金属層の厚さを制御することができるため、比表面積を大きくして触媒活性を高めることができる。 Further, in the exhaust gas purifying catalyst, it is practical and preferable that the noble metal layer is formed by coating at least a part of the surface of the fine particles using a plating method or a compound decomposition method. When the noble metal layer is formed by a plating method or a compound decomposition method, the thickness of the noble metal layer can be controlled as described later, so that the specific surface area can be increased and the catalytic activity can be increased.

次に、本発明の実施の形態に係る排ガス浄化用触媒の調製方法について説明する。本発明の実施の形態に係る排ガス浄化用触媒の調製方法は、無機化合物から形成される微粒子の表面の一部に、めっき法又は化合物分解法を用いて一種以上の貴金属から形成される貴金属層を被覆して触媒活性成分とする触媒活性成分調製工程と、触媒活性成分を基材上に担持する担持工程と、を含むものである。本調製方法によれば、貴金属の比表面積を大きくすることができ、貴金属間の距離を広げて貴金属の分散性を高めることができる。この結果、高温耐久性に優れ、触媒活性の高い排ガス浄化用触媒を得ることができる。 Next, a method for preparing an exhaust gas purifying catalyst according to an embodiment of the present invention will be described. A method for preparing an exhaust gas purifying catalyst according to an embodiment of the present invention includes a noble metal layer formed from one or more kinds of noble metals on a part of the surface of fine particles formed from an inorganic compound using a plating method or a compound decomposition method. A catalytic active component preparation step of coating the catalyst to form a catalytic active component, and a supporting step of supporting the catalytic active component on the substrate. According to this preparation method, the specific surface area of the noble metal can be increased, and the dispersibility of the noble metal can be enhanced by increasing the distance between the noble metals. As a result, an exhaust gas purifying catalyst having excellent high temperature durability and high catalytic activity can be obtained.

上記排ガス浄化用触媒の調製方法の触媒活性成分調整工程において、めっき処理を用いて、触媒活性成分を調整する工程を図１により説明する。 In the catalyst active component adjustment step of the method for preparing the exhaust gas purifying catalyst, the step of adjusting the catalyst active component using plating is described with reference to FIG.

図１に示すように、まず、長軸方向の径が30nmのアルミナ粒子１を用いて、アルミナ粒子１表面の一部にPtめっき処理をする（第１段階Ａ（前処理））。すると、アルミナ粒子１の表面の一部にPtめっき層２が薄く形成される。その後、再度めっき処理をする（第２段階Ｂ（正規Ptめっき処理））。正規Ptめっき処理では、前処理で形成されたPtめっき層２上に、選択的にPtめっきが施されてPt貴金属層３の厚さが増大したPtめっき粒子となる。 As shown in FIG. 1, first, Pt plating treatment is performed on a part of the surface of the alumina particles 1 using alumina particles 1 having a major axis diameter of 30 nm (first stage A (pretreatment)). Then, a thin Pt plating layer 2 is formed on a part of the surface of the alumina particles 1. Thereafter, the plating process is performed again (second stage B (regular Pt plating process)). In the regular Pt plating treatment, Pt plating particles selectively formed on the Pt plating layer 2 formed in the pretreatment to increase the thickness of the Pt noble metal layer 3 are obtained.

また、触媒活性成分調整工程における貴金属層を形成する貴金属の比表面積を16m²/g〜175m²/gとすることが好ましい。貴金属の比表面積を本範囲に規定した理由は、比表面積が16m²/g未満になると比表面積が小さくなりすぎて高い触媒活性が得られないからであり、逆に、比表面積が175m²/gを超える場合は、無機化合物の微粒子径が小さく成りすぎ、所謂含浸法と変わらなくなるからである。 Further, it is preferable that the specific surface area of the noble metal forming the noble metal layer in the catalytically active component adjusting step and 16m ^² / g~175m ² / g. The reason for defining the specific surface area of the precious metal in the range is because the specific surface area of 16m ² / when g is less than the specific surface area can not be obtained a high catalytic activity becomes too small, on the contrary, a specific surface area of 175 m ² / If it exceeds g, the fine particle diameter of the inorganic compound becomes too small, which is the same as the so-called impregnation method.

さらに、めっき法は、無電解めっき法を用いることが好ましく、めっき液中の貴金属量に応じて、微粒子上に形成する貴金属層の被覆率及び厚さを制御するものである。一方、化合物分解法は、微粒子に塗布する貴金属化合物の液量及び濃度に応じて、微粒子上に形成した貴金属層の被覆率及び厚さを制御するものである。本調製方法によれば、微粒子を被覆する貴金属の被覆率及び貴金属の比表面積を正確に制御することができる。 Further, the electroless plating method is preferably used as the plating method, and the coverage and thickness of the noble metal layer formed on the fine particles are controlled according to the amount of the noble metal in the plating solution. On the other hand, the compound decomposition method controls the coverage and thickness of the noble metal layer formed on the fine particles according to the amount and concentration of the noble metal compound applied to the fine particles. According to this preparation method, the coverage of the noble metal covering the fine particles and the specific surface area of the noble metal can be accurately controlled.

以下、実施例及び比較例を用いて具体的に説明するが、本発明の排ガス浄化用触媒は、例示した実施例に限定されるものではないことはもちろんである。 Hereinafter, although it demonstrates concretely using an Example and a comparative example, it cannot be overemphasized that the catalyst for exhaust gas purification of this invention is not limited to the illustrated Example.

＜実施例１＞
実施例１では、径が5nmのセリアを使用して調製したPt厚0.3nmのPt粒子Aを用いた。 <Example 1>
In Example 1, Pt particles A having a Pt thickness of 0.3 nm prepared using ceria having a diameter of 5 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）133.3ml（Pt量4g）、アンモニア水（28％）133.3ml、TP-502用還元剤133.3mlを順次加えた。これに純水約900ml、TP-502用めっき開始剤50ml、純水をさらに加えて1Lに調整した。調製した溶液中にセリア（径5nm）10.9gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し、50分で70℃まで温度を上げて、70℃で10分間保った。めっき液からガスが発生していないことを確認した後、めっき液の液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥し、一部Pt被覆層付きセリア(Pt厚さ:0.3nm)粒子を調製した。この粒子のPt含有量は26.84％であった（Pt粒子A）。Pt粒子A をTEMで観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が6割以上であり、Ptの比表面積は175 m²/gであった。 To the plating tank (1.5 L), TP-502 plating solution (Tanaka Kikinzoku Kogyo) 133.3 ml (Pt amount 4 g), ammonia water (28%) 133.3 ml, and TP-502 reducing agent 133.3 ml were sequentially added. About 900 ml of pure water, 50 ml of a plating initiator for TP-502, and pure water were further added to adjust to 1 L. While adding 10.9g of ceria (diameter 5nm) to the prepared solution and stirring with a stirrer, the plating tank was gradually heated with a water bath, the temperature was raised to 70 ° C in 50 minutes, and kept at 70 ° C for 10 minutes. . After confirming that no gas is generated from the plating solution, the plating solution is cooled to room temperature and filtered, washed repeatedly with pure water and dried, partially with ceria with a Pt coating layer (Pt thickness: 0.3 nm) particles were prepared. The Pt content of these particles was 26.84% (Pt particles A). When the Pt particles A were observed with TEM, Pt was adhered to only a part of the Pt particles A, 60% or more of the portions were not adhered with Pt, and the specific surface area of Pt was 175 m ² / g.

アルミナ基材（γ-アルミナに酸化セリウム9％、酸化ジルコニウム6％、酸化ランタン6％を複合化したもの）124.25g、セリア基材（セリアに酸化ジルコニウムを25％複合化したもの）45.875g、ベーマイトアルミナ1.6g、及びPt粒子A2.725gをボールミルに加えた後、さらに、水307.5g、10％硝酸水溶液17.5ｇを加えて、Pt粒子を分散させると共に粉末を粉砕し、平均粒径3μmのスラリとした（スラリa）。 124.25g of alumina base material (composite of γ-alumina 9% cerium oxide, 6% zirconium oxide, 6% lanthanum oxide), ceria base material (composite ceria 25% zirconium oxide) 45.875g, After adding 1.6 g of boehmite alumina and 2.725 g of Pt particles A to a ball mill, 307.5 g of water and 17.5 g of a 10% nitric acid aqueous solution were added to disperse the Pt particles and pulverize the powder to obtain an average particle size of 3 μm. Slurry (Slurry a).

次に、ジルコニウムとして3％を含むγ-アルミナと酸化ジルコニウム複合化合物に硝酸ロジウムを含浸し、ロジウム0.6％担持粉末を調製した。また、酸化ジルコニウムに酸化セリウムを24％複合化してジルコニア基材を調製した。ロジウム0.6％担持粉末116.55g、ジルコニア基材44.45g、アルミナ基材11g、ベーマイトアルミナ3gを順次ボールミルに加えた後、さらに、水307.5g、10％硝酸水溶液17.5gを加えて粉砕して平均粒径3μmのスラリとした（スラリR）。 Next, rhodium nitrate was impregnated with a composite compound of γ-alumina and zirconium oxide containing 3% as zirconium to prepare 0.6% rhodium-supported powder. A zirconia base material was prepared by compounding 24% of cerium oxide with zirconium oxide. After adding 116.55g of rhodium 0.6% supported powder, 44.45g of zirconia base material, 11g of alumina base material, and 3g of boehmite alumina to the ball mill in order, further add 307.5g of water and 17.5g of 10% nitric acid aqueous solution to grind the average particle A slurry with a diameter of 3 μm was used (Slurry R).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリａを141g/Lコーティングした後、乾燥し、その後、スラリＲを59g/Lコーティングし、乾燥後、400℃で焼成して実施例１の試料とした。得られた実施例１の触媒は、Pt 0.587g/L、Rh0.236g/Lを各々担持した触媒である。 The slurry carrier is coated with 141g / L of slurry a on a honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mil, dried, and then coated with slurry R of 59g / L, dried and fired at 400 ° C. The sample of Example 1 was obtained. The obtained catalyst of Example 1 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

＜実施例２＞
実施例２では、径が10nmのセリアを使用して調製したPt厚0.5nmのPt粒子Bを用いた。 <Example 2>
In Example 2, Pt particles B having a Pt thickness of 0.5 nm prepared using ceria having a diameter of 10 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた。さらに、純水約900mlまで加えた後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液にセリア（径10nm）12.52gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱して50分で70℃まで温度を上げて、10分間、70℃を保持した。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥した後、一部Pt被覆層付きアルミナ(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は13.77％であった（Ptめっき粒子b）。TEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が6割以上であった。 TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo) 66.7 ml (Pt amount 2 g), ammonia water (28%) 66.7 ml, and TP-502 reducing agent 66.7 ml were sequentially added to the plating tank (1.5 L). Further, after adding pure water to about 900 ml, 50 ml of a plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. While adding 12.52 g of ceria (diameter 10 nm) to this solution and stirring with a stirrer, the plating bath was gradually heated in a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas was generated from the plating solution, the solution temperature was lowered to room temperature, filtered, washed repeatedly with pure water and dried, and then partially coated with alumina with a Pt coating layer (Pt thickness: 0.278 nm ) Particles were prepared. The Pt content of these particles was 13.77% (Pt plated particles b). When observed by TEM, Pt was attached only to a part, and the place where Pt was not attached was 60% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）58.7ml（Pt量1.76g）、アンモニア水（28％）58.7mlを順次加えた後、TP-502用還元剤58.7mlを加えた。さらに、純水約900mlまで加えた後、TP-502用めっき開始剤50mlを加えて1Lに調整した。この溶液に前述したPtめっき粒子b14.52gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し、50分で70℃まで温度を上げて10分間、70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥し、一部Pt被覆層付きセリア(Pt厚さ:0.5nm)粒子を調製した。この粒子のPt含有量は23.1％であった（Pt粒子B）。TEMにてPt粒子Bを観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が6割以上であった。Ptの比表面積は102m²/gであった。 Next, after adding 58.7 ml of TP-502 plating solution (Tanaka Kikinzoku Kogyo) 58.7 ml (Pt amount 1.76 g) and 58.7 ml of ammonia water (28%) to the plating tank (1.5 L) in turn, a reducing agent for TP-502 58.7 ml was added. Furthermore, after adding about 900 ml of pure water, 50 ml of a plating initiator for TP-502 was added to adjust to 1 L. While adding 14.52 g of the above-mentioned Pt plating particles b to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath, and the temperature was raised to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, dry with repeated washing with pure water, partly ceria with Pt coating layer (Pt thickness: 0.5 nm) Particles were prepared. The Pt content of these particles was 23.1% (Pt particles B). When observing Pt particles B by TEM, Pt was covered at the places where Pt was previously attached, and more than 60% of the places were not covered by Pt. The specific surface area of Pt was 102 m ² / g.

アルミナ基材（γ-アルミナに酸化セリウム9％、酸化ジルコニウム6％、酸化ランタン6％を複合化したもの）124.8g、セリア基材（セリアに酸化ジルコニウムを25％複合化したもの）45.434g、ベーマイトアルミナ1.6g及びPt粒子B3.166gをボールミルに加えた後、さらに水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕し、平均粒径3μmのスラリとした（スラリb）。 Alumina substrate (composite of γ-alumina with 9% cerium oxide, 6% zirconium oxide, 6% lanthanum oxide) 124.8g, ceria substrate (composite ceria with 25% zirconium oxide) 45.434g, After adding 1.6g of boehmite alumina and 3.166g of Pt particles B to the ball mill, add 307.5g of water and 17.5g of 10% nitric acid aqueous solution to disperse the Pt particles and pulverize the powder. (Slurry b).

次に、ジルコニウムとして3％を含むγ-アルミナと酸化ジルコニウム複合化合物に硝酸ロジウムを含浸し、ロジウム0.6％担持粉末を調製した。また、酸化ジルコニウムに酸化セリウムを24％複合化してジルコニア基材を調製した。ロジウム0.6％担持粉末116.55g、ジルコニア基材44.45g、アルミナ基材11g、ベーマイトアルミナ3gを順次ボールミルに加えた後、水307.5g、10％硝酸水溶液17.5gを加えて粉砕し、平均粒径3μmのスラリとした（スラリR）。 Next, rhodium nitrate was impregnated with a composite compound of γ-alumina and zirconium oxide containing 3% as zirconium to prepare 0.6% rhodium-supported powder. A zirconia base material was prepared by compounding 24% of cerium oxide with zirconium oxide. 116.55g of rhodium 0.6% supported powder, 44.45g of zirconia base material, 11g of alumina base material and 3g of boehmite alumina were sequentially added to the ball mill, and then pulverized with 307.5g of water and 17.5g of 10% nitric acid aqueous solution, and an average particle size of 3μm (Slurry R).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリaを141g/Lコーティングした後、乾燥し、さらにスラリＲを59g/Lコーティングして乾燥した後、400℃で焼成して実施例２の試料とした。得られた実施例２の触媒は、Pt 0.587ｇ/L、Rh0.236ｇ/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mils is coated with 141g / L of slurry a, then dried, further coated with 59g / L of slurry R, dried and fired at 400 ° C. The sample of Example 2 was obtained. The obtained catalyst of Example 2 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

＜実施例３＞
実施例３では、径が20nmのアルミナを使用して調製したPt厚1nmのPt粒子Cを用いた。 <Example 3>
In Example 3, Pt particles C having a Pt thickness of 1 nm prepared using alumina having a diameter of 20 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加え、さらに、純水約900mlまで加えた後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液にアルミナ（径20nm）13.04gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱して50分で70℃まで温度を上げ、10分間、70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥した後、一部Pt被覆層付きアルミナ(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は13.30％であった（Ptめっき粒子c）。TEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が6割以上であった。 Add TP-502 plating solution (Tanaka Kikinzoku Kogyo) 66.7ml (Pt amount 2g), ammonia water (28%) 66.7ml, TP-502 reducing agent 66.7ml to the plating tank (1.5L), After adding about 900 ml of water, 50 ml of a plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. To this solution, 13.04 g of alumina (diameter 20 nm) was added, and while stirring with a stirrer, the plating tank was gradually heated in a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas was generated from the plating solution, the solution temperature was lowered to room temperature, filtered, washed repeatedly with pure water and dried, and then partially coated with alumina with a Pt coating layer (Pt thickness: 0.278 nm ) Particles were prepared. The Pt content of these particles was 13.30% (Pt plated particles c). When observed by TEM, Pt was attached only to a part, and the place where Pt was not attached was 60% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）190.5ml（Pt量5.71g）、アンモニア水（28％）190.5ml、TP-502用還元剤190.5mlを順次加えた後、純水約900mlまで加えた。さらに、TP-502用めっき開始剤50ml加えた後、純水を加えて１Lに調整した。この溶液に前述したPtめっき粒子c15.04gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱して50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して一部Pt被覆層付きアルミナ(Pt厚さ:１nm)粒子を調製した。この粒子のPt含有量は37.17％であった(Pt粒子C)。TEMにてPt粒子Cを観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が6割以上であった。また、Ptの比表面積は51.1 m²/gであった。 Next, TP-502 plating solution (Tanaka Kikinzoku Kogyo) 190.5ml (Pt amount 5.71g), ammonia water (28%) 190.5ml, and TP-502 reducing agent 190.5ml were added to the plating tank (1.5L) in this order. After that, about 900 ml of pure water was added. Furthermore, after adding 50 ml of a plating initiator for TP-502, pure water was added to adjust to 1 L. The Pt plating particles c15.04 g described above were added to this solution and the plating tank was gradually heated with a water bath while stirring with a stirrer to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas was generated from the plating solution, the solution temperature was lowered to room temperature, filtered, and washed with pure water repeatedly to prepare alumina particles with a Pt coating layer (Pt thickness: 1 nm). . The Pt content of these particles was 37.17% (Pt particles C). When observing the Pt particles C by TEM, Pt was covered at the places where Pt had previously been adhered, and more than 60% of the places were not covered with Pt. The specific surface area of Pt was 51.1 m ² / g.

実施例１で調製したアルミナ基材122.832g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g及びPt粒子C1.968gをボールミルに順次加えた後、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕して、平均粒径3μmのスラリとした（スラリc）。 After sequentially adding 122.832 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina, and 1.968 g of Pt particles to a ball mill, 307.5 g of water and a 10% nitric acid aqueous solution were added. 17.5 g was added to disperse the Pt particles and the powder was pulverized to obtain a slurry having an average particle size of 3 μm (slurry c).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリcを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングして、乾燥後400℃で焼成して実施例３の試料とした。得られた実施例３の触媒は、Pt 0.587ｇ/L、Rh0.236ｇ/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) having a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry c, dried, and further coated with 59g / L of slurry R prepared in Example 1, and dried at 400 ° C. The sample of Example 3 was fired. The obtained catalyst of Example 3 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

＜実施例４＞
実施例４では、径が30nmのアルミナを使用して調製したPt厚1nmのPt粒子Dを用いた。 <Example 4>
In Example 4, Pt particles D having a Pt thickness of 1 nm prepared using alumina having a diameter of 30 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた後、純水を約900mlまで加えた。その後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液にアルミナ（径30nm）19.78gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱して50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きアルミナ(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は9.18％であった（Ptめっき粒子d）。Ptめっき粒子dをTEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が6割以上であった。 TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) 66.7ml (Pt amount 2g), ammonia water (28%) 66.7ml, reducing agent 6TP Water was added to about 900 ml. Thereafter, 50 ml of a plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. 19.78 g of alumina (diameter 30 nm) was added to this solution, and while stirring with a stirrer, the plating tank was gradually heated with a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, repeatedly wash with pure water, and dry, partially alumina with Pt coating layer (Pt thickness: 0.278 nm) particles Was prepared. The Pt content of these particles was 9.18% (Pt plated particles d). When the Pt plating particles d were observed with a TEM, Pt was adhered to only a part, and the location where Pt was not adhered was 60% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）185ml（Pt量5.55g）、アンモニア水（28％）185ml、TP-502用還元剤185mlを順次加えた後、これに純水を約900mlまで加えた。その後、TP-502用めっき開始剤50mlを加えた後に純水を加えて1Lに調整した。この溶液に前述したPtめっき粒子d 21.78gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げて、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きアルミナ(Pt厚さ:１nm)粒子を調製した。この粒子のPt含有量は27.62％であった（Pt粒子D）。Pt粒子DをTEMにて観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が6割以上であった。また、Ptの比表面積は49.6m²/gであった。 Next, 185 ml of TP-502 plating solution (Tanaka Kikinzoku Kogyo) 185 ml (5.55 g of Pt), 185 ml of ammonia water (28%), and 185 ml of reducing agent for TP-502 were sequentially added to the plating tank (1.5 L). To this, pure water was added up to about 900 ml. Thereafter, 50 ml of a plating initiator for TP-502 was added, and then pure water was added to adjust to 1 L. While adding 21.78 g of the aforementioned Pt plating particles d to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter it, wash it repeatedly with pure water, and dry it. Some alumina particles with Pt coating layer (Pt thickness: 1 nm) are obtained. Prepared. The Pt content of these particles was 27.62% (Pt particles D). When Pt particles D were observed by TEM, Pt was covered at the places where Pt had been previously attached, and more than 60% of the places were not covered with Pt. The specific surface area of Pt was 49.6 m ² / g.

実施例１で調製したアルミナ基材122.152g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g、及び前述したPt粒子D2.648gを順次ボールミルに加えた後、水307.5g、10％硝酸水溶液17.5gを加えて、Pt被覆層付き粒子を分散させると共に粉末を粉砕して、平均粒径3μmのスラリとした（スラリd）。 After sequentially adding 122.152 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina, and 2.648 g of the above-mentioned Pt particles D, 307.5 g of water, 10 17.5 g of an aqueous nitric acid solution was added to disperse the particles with the Pt coating layer and the powder was pulverized to obtain a slurry having an average particle diameter of 3 μm (slurry d).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリdを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングし、乾燥後、400℃で焼成して実施例４の試料とした。得られた実施例４の触媒は、Pt0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry d, dried, and further coated with 59g / L of slurry R prepared in Example 1, and dried at 400 ° C. The sample of Example 4 was fired. The obtained catalyst of Example 4 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L.

＜実施例５＞
実施例５では、径が50nmのチタンシリケートを使用して調製したPt厚2nmのPt粒子Eを用いた。 <Example 5>
In Example 5, Pt particles E having a Pt thickness of 2 nm prepared using titanium silicate having a diameter of 50 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた。その後、これに純水を約900mlまで加えてTP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液にチタンシリケート（径50nm）41.48gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥し、一部Pt被覆層付きチタンシリケート(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は4.60％であった（Ptめっき粒子e）。TEMにてPtめっき粒子eを観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が7割以上であった。 TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo) 66.7 ml (Pt amount 2 g), ammonia water (28%) 66.7 ml, and TP-502 reducing agent 66.7 ml were sequentially added to the plating tank (1.5 L). Thereafter, pure water was added to about 900 ml, 50 ml of a plating initiator for TP-502 was added thereto, and pure water was further added to adjust to 1 L. While adding 41.48 g of titanium silicate (diameter 50 nm) to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, repeat washing with pure water and dry, partially with titanium silicate with Pt coating layer (Pt thickness: 0.278 nm) ) Particles were prepared. The Pt content of these particles was 4.60% (Pt plated particles e). When observing the Pt plating particles e with TEM, Pt was adhered to only a part, and the portion where Pt was not adhered was 70% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）215.5ml（Pt量6.46g）、アンモニア水（28％）215.5ml、TP-502用還元剤215.5mlを順次加えた後、純水を約900mlまで加えた。その後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液に前述したPtめっき粒子e20.96gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間、70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きチタンシリケート(Pt厚さ:2nm)粒子を調製した。この粒子のPt含有量は27.08％であった（Pt粒子E）。TEMにてPt粒子Eを観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が7割以上であった。また、Ptの比表面積は25.1m²/gであった。 Next, TP-502 plating solution (Tanaka Kikinzoku Kogyo) 215.5ml (Pt amount 6.46g), ammonia water (28%) 215.5ml, reducing agent 215.5ml for TP-502 was added to the plating tank (1.5L) sequentially. After that, pure water was added to about 900 ml. Thereafter, 50 ml of a plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. While adding the above-mentioned Pt plating particles e20.96 g to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, repeatedly wash with pure water, and dry, partially with a Pt coating layer titanium silicate (Pt thickness: 2 nm) particles Was prepared. The Pt content of the particles was 27.08% (Pt particles E). When observing Pt particles E by TEM, Pt was covered at the places where Pt had previously been adhered, and more than 70% of the places were not covered by Pt. The specific surface area of Pt was 25.1 m ² / g.

実施例１で調製したアルミナ基材122.099g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g、及びPt粒子E2.701gをボールミルに順次加えた後、さらに水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕して、平均粒径3μmのスラリとした（スラリe）。 After sequentially adding 122.099 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina, and 2.701 g of Pt particles, 307.5 g of water, 10% 17.5 g of an aqueous nitric acid solution was added to disperse the Pt particles and the powder was pulverized to obtain a slurry having an average particle diameter of 3 μm (slurry e).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリeを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングし、乾燥後400℃で焼成して、実施例５の試料とした。得られた実施例５の触媒は、Pt0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry e, dried, then coated with 59g / L of slurry R prepared in Example 1, dried and fired at 400 ° C Thus, a sample of Example 5 was obtained. The obtained catalyst of Example 5 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

＜実施例６＞
実施例６では、径が70nmのチタンシリケートを使用して調製したPt厚2nmのPt粒子Fを用いた。 <Example 6>
In Example 6, Pt particles F having a Pt thickness of 2 nm prepared using titanium silicate having a diameter of 70 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた後、これに純水を約900mlまで加えた。その後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液にチタンシリケート（径70nm）58.23gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥し、一部Pt被覆層付きチタンシリケート(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は3.32％であった（Ptめっき粒子f）。Ptめっき粒子fをTEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が7割以上であった。 TP-502 plating solution (made by Tanaka Kikinzoku Kogyo) 66.7ml (Pt amount 2g), ammonia water (28%) 66.7ml, TP-502 reducing agent 66.7ml was added to the plating tank (1.5L) in this order. Pure water was added to about 900 ml. Thereafter, 50 ml of a plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. While adding 58.23 g of titanium silicate (diameter 70 nm) to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, repeat washing with pure water and dry, partially with titanium silicate with Pt coating layer (Pt thickness: 0.278 nm) ) Particles were prepared. The Pt content of these particles was 3.32% (Pt plated particles f). When the Pt plated particles f were observed with a TEM, Pt was adhered to only a part, and the portion where Pt was not adhered was 70% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）150ml（Pt量4.501g）を加え、次にアンモニア水（28％）を150ml加え、TP-502用還元剤150ml加える。これに純水を約900mlまで加え、TP-502用めっき開始剤50mlを加えた後、さらに純水を加えて1Lに調整した。この溶液に前述のPtめっき粒子f20.687gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し、50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥し、一部Pt被覆層付きチタンシリケート(Pt厚さ:2nm)粒子を調製した。この粒子のPt含有量は20.59％であった（Pt粒子F）。TEMにてPt粒子Fを観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が7割以上であった。また、Ptの比表面積は24.6m²/gであった。 Next, 150 ml of TP-502 plating solution (Tanaka Kikinzoku Kogyo) 150 ml (4.51 g of Pt) is added to the plating tank (1.5 L), then 150 ml of ammonia water (28%) is added, and 150 ml of reducing agent for TP-502 Add. To this, pure water was added up to about 900 ml, and after adding 50 ml of a plating initiator for TP-502, pure water was further added to adjust to 1 L. While adding the above-mentioned Pt plating particle f20.687 g to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath, the temperature was raised to 70 ° C. in 50 minutes, and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the solution temperature to room temperature, filter, repeat washing with pure water and dry, partly titanium silicate with Pt coating layer (Pt thickness: 2 nm) Particles were prepared. The Pt content of these particles was 20.59% (Pt particles F). When observing the Pt particles F by TEM, Pt was coated on the places where Pt had previously been adhered, and more than 70% of the places were not covered with Pt. The specific surface area of Pt was 24.6 m ² / g.

実施例１で調製したアルミナ基材121.248g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g、及びPt粒子F3.552gをボールミルに順次加えた後、さらに、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕し、平均粒径3μmのスラリとした（スラリf）。 121.248 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina and 3.552 g of Pt particles F were sequentially added to a ball mill. 17.5 g of an aqueous nitric acid solution was added to disperse the Pt particles and the powder was pulverized to obtain a slurry having an average particle diameter of 3 μm (slurry f).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリｆを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングし、乾燥後、400℃で焼成して実施例６の試料とした。実施例６の触媒は、Pt0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) having a diameter of 36φ, 400 cells and 6 mils was coated with 141 g / L of slurry f, dried, and further coated with 59 g / L of slurry R prepared in Example 1, and dried at 400 ° C. The sample of Example 6 was fired. The catalyst of Example 6 is a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L.

＜実施例７＞
実施例７では、径が100nmのアルミニウムシリケートを使用して調製したPt厚3nmのPt粒子Gを用いた。 <Example 7>
In Example 7, Pt particles G having a Pt thickness of 3 nm prepared using aluminum silicate having a diameter of 100 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた。これに純水を約900mlまで加えた後、TP-502用めっき開始剤50mlを加えて、さらに純水を加えて1Lに調整した。この溶液にチタンシリケート（径70nm）83.47gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きチタンシリケート(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は2.34％であった（Ptめっき粒子g）。このPtめっき粒子gをTEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が7割以上であった。 TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo) 66.7 ml (Pt amount 2 g), ammonia water (28%) 66.7 ml, and TP-502 reducing agent 66.7 ml were sequentially added to the plating tank (1.5 L). After adding pure water up to about 900 ml, 50 ml of plating initiator for TP-502 was added, and pure water was further added to adjust to 1L. While adding 83.47 g of titanium silicate (diameter 70 nm) to this solution and stirring with a stirrer, the plating tank was gradually heated in a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, wash repeatedly with pure water and dry, partly titanium silicate with Pt coating layer (Pt thickness: 0.278 nm) Particles were prepared. The Pt content of these particles was 2.34% (Pt plated particles g). When this Pt plating particle g was observed by TEM, Pt was adhered only to a part, and the portion where Pt was not adhered was 70% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）166ml（Pt量4.98g）、アンモニア水（28％）166ml、TP-502用還元剤166mlを順次加えた。これに純水を約900mlまで加えた後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液に前述したPtめっき粒子g20.48gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きチタンシリケート(Pt厚さ:3nm)粒子を調製した。この粒子のPt含有量は21.44％であった（Pt粒子G）。TEMにてPt粒子Gを観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が7割以上であった。また、Ptの比表面積は16.5m²/gであった。 Next, 166 ml (Pt amount 4.98 g) of TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo), 166 ml of ammonia water (28%), and 166 ml of a reducing agent for TP-502 were sequentially added to the plating tank (1.5 L). To this was added pure water up to about 900 ml, 50 ml of plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. While adding 20.48 g of the above-mentioned Pt plating particles to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, the solution temperature is lowered to room temperature, filtered, washed repeatedly with pure water and dried, and some of the titanium silicate with a Pt coating layer (Pt thickness: 3 nm) Prepared. The Pt content of these particles was 21.44% (Pt particles G). When observing the Pt particles G by TEM, Pt was covered at the places where Pt had previously been adhered, and more than 70% of the places were not covered with Pt. The specific surface area of Pt was 16.5 m ² / g.

実施例１で調製したアルミナ基材121.194g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g、及びPt粒子G3.606gをボールミルに加えた後、さらに、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕して平均粒径3μmのスラリとした（スラリg）。 After adding 121.194 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina, and 3.606 g of Pt particles, 307.5 g of water, 10% 17.5 g of an aqueous nitric acid solution was added to disperse the Pt particles and the powder was pulverized to obtain a slurry having an average particle size of 3 μm (slurry g).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリgを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングして、乾燥後、400℃で焼成して実施例７の試料とした。得られた実施例７の触媒は、Pt 0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) having a diameter of 36φ, 400 cells and 6 mils was coated with 141 g / L of slurry g, dried, and further coated with 59 g / L of slurry R prepared in Example 1, and dried at 400 ° C. The sample of Example 7 was baked. The obtained catalyst of Example 7 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

＜実施例８＞
実施例８では、径が30nmのアルミナを使用して調製したPt厚0.5nm〜2nmのPt粒子Hを用いた。 <Example 8>
In Example 8, Pt particles H having a Pt thickness of 0.5 nm to 2 nm prepared using alumina having a diameter of 30 nm were used.

20nmのアルミナ粒子20gにジニトロジアミンPt溶液を噴霧して、アルミナ粒子がスラリ化しない状態で噴霧を止めて乾燥した。再び噴霧して、乾燥を繰り返し、400℃で焼成して化合物を分解した。この粒子のPt含有量は27.6％であった（Pt粒子H）。このPt粒子HをTEMにて観察したところ、Ptは粒子の所々に付着しており、Ptが付着していない箇所は６割以上であった。観察した結果、Ptの厚さは0.5nm〜2nmと各種存在しており、また、Ptの比表面積は約40m²/gであった。 Dinitrodiamine Pt solution was sprayed onto 20 g of 20 nm alumina particles, and the spraying was stopped and the alumina particles were not slurried and dried. Spraying was repeated, drying was repeated, and the compound was decomposed by baking at 400 ° C. The Pt content of these particles was 27.6% (Pt particles H). When the Pt particles H were observed with a TEM, Pt was adhered to the portions of the particles, and the locations where Pt was not adhered was 60% or more. As a result of observation, various thicknesses of Pt existed from 0.5 nm to 2 nm, and the specific surface area of Pt was about 40 m ² / g.

実施例１で調製したアルミナ基材122.15g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g及びPt粒子H2.65gを順次ボールミルに加えた。その後、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に、粉末を粉砕して平均粒径3μmのスラリとした（スラリh）。 122.15 g of the alumina substrate prepared in Example 1, 48.6 g of the ceria substrate prepared in Example 1, 1.6 g of boehmite alumina, and 2.65 g of Pt particles H were sequentially added to the ball mill. Thereafter, 307.5 g of water and 17.5 g of a 10% nitric acid aqueous solution were added to disperse the Pt particles, and the powder was pulverized into a slurry having an average particle diameter of 3 μm (slurry h).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリhを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングし、乾燥後400℃で焼成して、実施例８の試料とした。得られた実施例８の触媒は、Pt0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry h, dried, then coated with 59g / L of slurry R prepared in Example 1, dried and fired at 400 ° C Thus, a sample of Example 8 was obtained. The obtained catalyst of Example 8 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L.

＜比較例１＞
比較例１では、実施例１で調製したアルミナ基材にジニトロジアミン白金水溶液を含浸し、乾燥後、400℃で焼成して、Pt0.44％のアルミナ基材を調製した。また、実施例１で調製したセリア基材にジニトロジアミン白金水溶液を含浸し、乾燥した後、400℃で焼成してPt0.375 ％のセリア基材を調製した。 <Comparative Example 1>
In Comparative Example 1, the alumina base material prepared in Example 1 was impregnated with a dinitrodiamine platinum aqueous solution, dried, and then fired at 400 ° C. to prepare a Pt 0.44% alumina base material. Further, the ceria base material prepared in Example 1 was impregnated with a dinitrodiamine platinum aqueous solution, dried, and then fired at 400 ° C. to prepare a Pt 0.375% ceria base material.

Pt0.44％のアルミナ基材124.8g、Pt0.375 ％のセリア基材48.6g、ベーマイトアルミナ1.6gを順次ボールミルに加えた後、さらに、水307.5g、10％硝酸水溶液17.5gを加えて粉末を粉砕し、平均粒径3μmのスラリとした（スラリX）。 Pt 0.44% alumina base material 124.8g, Pt 0.375% ceria base material 48.6g, boehmite alumina 1.6g were added to the ball mill in order, and then 307.5g water and 17.5g nitric acid aqueous solution 17.5g were added. Was crushed into a slurry with an average particle size of 3 μm (Slurry X).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリXを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングし、乾燥後400℃で焼成して比較例１の試料とした。得られた比較例１の触媒は、Pt 0.587ｇ/L、Rh0.236ｇ/Lを各々担持した触媒であり、所謂、通常の貴金属を含浸した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ and 400 cells is coated with 141g / L of slurry X, dried, then coated with 59g / L of slurry R prepared in Example 1, dried and fired at 400 ° C Thus, a sample of Comparative Example 1 was obtained. The obtained catalyst of Comparative Example 1 is a catalyst that supports Pt 0.587 g / L and Rh 0.236 g / L, respectively, and is a catalyst impregnated with a so-called ordinary noble metal.

＜比較例２＞
比較例２では、径が3nmであるジルコニアを使用して調製したPt0.278nm厚のPt粒子Iを用いた。 <Comparative example 2>
In Comparative Example 2, Pt particles I having a Pt of 0.278 nm and prepared using zirconia having a diameter of 3 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2.0g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた。これに純水を約900mlまで加え、さらにTP-502用めっき開始剤50mlを加えた後、さらに純水を加えて1Lに調整した。この溶液にジルコニア（径3nm）2.61gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きジルコニア(Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は43.33％であった（Pt粒子I）。Pt粒子IをTEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が6割以上であった。また、Ptの比表面積は約200m²/gであった。 TP-502 plating solution (Tanaka Kikinzoku Kogyo) 66.7ml (Pt amount 2.0g), ammonia water (28%) 66.7ml, and TP-502 reducing agent 66.7ml were sequentially added to the plating tank (1.5L). To this was added pure water up to about 900 ml, and further 50 ml of a plating initiator for TP-502 was added, and further pure water was added to adjust to 1 L. While adding 2.61 g of zirconia (diameter 3 nm) to this solution and stirring with a stirrer, the plating tank was gradually heated in a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, the solution temperature is lowered to room temperature, filtered, washed repeatedly with pure water and dried, and some zirconia particles with a Pt coating layer (Pt thickness: 0.278 nm) Was prepared. The Pt content of these particles was 43.33% (Pt particles I). When the Pt particles I were observed by TEM, Pt was adhered only to a part, and the portion where Pt was not adhered was 60% or more. The specific surface area of Pt was about 200 m ² / g.

実施例１で調製したアルミナ基材123.112g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g、Pt粒子Iを1.688g順次ボールミルに加えた。その後、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕して平均粒径3μmのスラリとした（スラリi）。 123.112 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina, and 1.688 g of Pt particles I were sequentially added to a ball mill. Thereafter, 307.5 g of water and 17.5 g of a 10% nitric acid aqueous solution were added to disperse the Pt particles and the powder was pulverized to obtain a slurry having an average particle diameter of 3 μm (slurry i).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリiを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングし、乾燥後、400℃で焼成して比較例２の試料とした。得られた比較例２の触媒は、Pt0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry i, dried, and then 59g / L of slurry R prepared in Example 1 was coated. The sample of Comparative Example 2 was fired. The obtained catalyst of Comparative Example 2 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L.

＜比較例３＞
比較例３では、径が150nmのチタン酸バリウムを使用して調製したPt厚5nm のPt粒子Jを用いた。 <Comparative Example 3>
In Comparative Example 3, Pt particles J having a Pt thickness of 5 nm prepared using barium titanate having a diameter of 150 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた。これに純水を約900mlまで加えた後、TP-502用めっき開始剤50mlを加え、さらに純水を加えて1Lに調整した。この溶液にチタン酸バリウム（径150nm）254gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し50分で70℃まで温度を上げ、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きチタン酸バリウム (Pt厚さ:0.278nm)粒子を調製した。この粒子のPt含有量は0.78％であった（Ptめっき粒子j）。このPtめっき粒子jをTEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が7割以上であった。 TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo) 66.7 ml (Pt amount 2 g), ammonia water (28%) 66.7 ml, and TP-502 reducing agent 66.7 ml were sequentially added to the plating tank (1.5 L). To this was added pure water up to about 900 ml, 50 ml of plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. While adding 254 g of barium titanate (diameter 150 nm) to this solution and stirring with a stirrer, the plating tank was gradually heated in a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. After confirming that no gas was generated from the plating solution, the solution temperature was lowered to room temperature, filtered, washed repeatedly with pure water and dried, and partly barium titanate with a Pt coating layer (Pt thickness: 0.278 nm ) Particles were prepared. The Pt content of these particles was 0.78% (Pt plated particles j). When this Pt plating particle j was observed by TEM, Pt was adhered only to a part, and the portion where Pt was not adhered was 70% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）95.3ml（Pt量2.858g）、アンモニア水（28％）95.3ml、TP-502用還元剤95.3mlを順次加えた。これに純水を約900mlまで加えて、TP-502用めっき開始剤50mlを加えた後、さらに、純水を加えて1Lに調整した。この溶液に前述したPt粒子j20.157gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し、50分で70℃まで温度を上げて、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きチタン酸バリウム(Pt厚さ5nm)粒子を調製した。この粒子のPt含有量は13.1％であった（Pt粒子J）。TEMにてPt粒子Jを観察したところ、Ptは前にPtを付着した箇所に被覆されており、Ptが被覆されていない箇所が7割以上であった。また、Ptの比表面積は約9m²/gであった。 Next, 95.3 ml of TP-502 plating solution (Tanaka Kikinzoku Kogyo) 95.3 ml (Pt amount 2.858 g), 95.3 ml of ammonia water (28%), and 95.3 ml of reducing agent for TP-502 were sequentially added to the plating tank (1.5 L). It was. To this was added pure water up to about 900 ml, and after adding 50 ml of a plating initiator for TP-502, pure water was further added to adjust to 1 L. While adding 20.157 g of the above-mentioned Pt particles j to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath, the temperature was raised to 70 ° C. in 50 minutes, and maintained at 70 ° C. for 10 minutes. After confirming that no gas is generated from the plating solution, lower the temperature of the solution to room temperature, filter, repeatedly wash with pure water, and dry, partially with barium titanate (Pt thickness 5 nm) particles with Pt coating layer Was prepared. The Pt content of these particles was 13.1% (Pt particles J). When observing Pt particles J by TEM, Pt was covered at the places where Pt had previously been adhered, and more than 70% of the places were not covered with Pt. The specific surface area of Pt was about 9 m ² / g.

実施例１で調製したアルミナ基材119.217g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g、及びPt粒子J5.583gをボールミルに加えた後、さらに、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に、粉末を粉砕して平均粒径3μmのスラリとした（スラリj）。 119.217 g of the alumina base material prepared in Example 1, 48.6 g of the ceria base material prepared in Example 1, 1.6 g of boehmite alumina, and 5.583 g of Pt particles J were added to a ball mill, and then 307.5 g of water, 10% 17.5 g of an aqueous nitric acid solution was added to disperse the Pt particles, and the powder was pulverized into a slurry having an average particle size of 3 μm (slurry j).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリjを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングして、乾燥後400℃で焼成して比較例３の試料とした。得られた比較例３の触媒は、Pt 0.587g/L、Rh0.236g/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) with a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry j, dried, and then 59g / L of slurry R prepared in Example 1 was coated. The sample of Comparative Example 3 was fired. The obtained catalyst of Comparative Example 3 was a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

＜比較例４＞
比較例４では、径が200nmのチタン酸バリウムを使用して調製したPt厚5nm のPt粒子Kを用いた。 <Comparative example 4>
In Comparative Example 4, Pt particles K having a Pt thickness of 5 nm prepared using barium titanate having a diameter of 200 nm were used.

めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）66.7ml（Pt量2g）、アンモニア水（28％）66.7ml、TP-502用還元剤66.7mlを順次加えた。これに純水を約900mlまで加えた後、TP-502用めっき開始剤50mlを加え、さらに、純水を加えて1Lに調整した。この溶液にチタン酸バリウム（径200nm）602gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱して50分で70℃まで温度を上げて、10分間、70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返し乾燥し、一部Pt被覆層付きチタン酸バリウム(Pt厚さ0.278nm)粒子を調製した。この粒子のPt含有量は0.33％であった（Ptめっき粒子k）。Ptめっき粒子kをTEMにて観察したところ、一部分だけにPtが付着しており、Ptが付着していない箇所が7割以上であった。 TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo) 66.7 ml (Pt amount 2 g), ammonia water (28%) 66.7 ml, and TP-502 reducing agent 66.7 ml were sequentially added to the plating tank (1.5 L). To this was added pure water up to about 900 ml, 50 ml of plating initiator for TP-502 was added, and pure water was further added to adjust to 1 L. While adding 602 g of barium titanate (diameter 200 nm) to this solution and stirring with a stirrer, the plating bath was gradually heated in a water bath to raise the temperature to 70 ° C. in 50 minutes and maintained at 70 ° C. for 10 minutes. . After confirming that no gas is generated from the plating solution, the solution temperature is lowered to room temperature, filtered, washed repeatedly with pure water and dried, and partly barium titanate with a Pt coating layer (Pt thickness 0.278 nm) Particles were prepared. The Pt content of these particles was 0.33% (Pt plated particles k). When the Pt plating particles k were observed by TEM, Pt was attached only to a part, and the place where Pt was not attached was 70% or more.

次に、めっき槽（1.5L）にTP-502めっき液（田中貴金属工業製）72ml（Pt量2.16g）、アンモニア水（28％）72ml、TP-502用還元剤72mlを順次加えた。その後、これに純水を約900mlまで加え、TP-502用めっき開始剤50mlを加えた後、さらに純水を加えて1Lに調整した。この溶液に前述したPtめっき粒子k20.066gを加えてスターラーで攪拌しながら、めっき槽をウオーターバスで徐々に加熱し、50分で70℃まで温度を上げて、10分間70℃を保った。めっき液からガスが発生していないことを確認した後、液温を室温まで下げてろ過し、純水で洗浄を繰り返して乾燥し、一部Pt被覆層付きチタン酸バリウム(Pt厚さ5nm)粒子を調製した。この粒子のPt含有量は10.01％であった（Pt粒子K）。TEMにてPt粒子Kを観察したところ、前にPtを付着した箇所にPtが被覆されており、Ptが被覆されていない箇所が7割以上であった。また、Ptの比表面積は約9m²/gであった。 Next, 72 ml of TP-502 plating solution (manufactured by Tanaka Kikinzoku Kogyo), 72 ml of ammonia water (28%), and 72 ml of reducing agent for TP-502 were sequentially added to the plating tank (1.5 L). Thereafter, pure water was added to about 900 ml, and after adding 50 ml of a plating initiator for TP-502, pure water was further added to adjust to 1 L. While adding the above-mentioned Pt plating particles k20.066g to this solution and stirring with a stirrer, the plating tank was gradually heated with a water bath, the temperature was raised to 70 ° C in 50 minutes, and maintained at 70 ° C for 10 minutes. After confirming that no gas is generated from the plating solution, lower the solution temperature to room temperature, filter, repeat washing with pure water and dry, partly barium titanate with Pt coating layer (Pt thickness 5 nm) Particles were prepared. The Pt content of these particles was 10.01% (Pt particles K). When observing the Pt particles K by TEM, Pt was coated on the places where Pt was previously attached, and more than 70% of the places were not covered with Pt. The specific surface area of Pt was about 9 m ² / g.

実施例１で調製したアルミナ基材117.494g、実施例１で調製したセリア基材48.6g、ベーマイトアルミナ1.6g及びPt粒子K7.306gを順次ボールミルに加えた。その後、水307.5g、10％硝酸水溶液17.5gを加えて、Pt粒子を分散させると共に粉末を粉砕して平均粒径3μmのスラリとした（スラリk）。 117.494 g of the alumina substrate prepared in Example 1, 48.6 g of the ceria substrate prepared in Example 1, 1.6 g of boehmite alumina, and 7.306 g of Pt particles K were sequentially added to the ball mill. Thereafter, 307.5 g of water and 17.5 g of a 10% nitric acid aqueous solution were added to disperse the Pt particles, and the powder was pulverized into a slurry having an average particle size of 3 μm (slurry k).

直径36φ、400セル6ミルのハニカム担体（容量0.04L）にスラリkを141g/Lコーティングし、乾燥後、さらに実施例１で調製したスラリRを59g/Lコーティングして、乾燥後400℃で焼成して比較例４の試料とした。得られた比較例４の触媒は、Pt 0.587ｇ/L、Rh0.236ｇ/Lを各々担持した触媒である。 A honeycomb carrier (capacity 0.04L) having a diameter of 36φ, 400 cells and 6 mils was coated with 141g / L of slurry k, dried, and further coated with 59g / L of slurry R prepared in Example 1, and dried at 400 ° C. The sample of Comparative Example 4 was fired. The obtained catalyst of Comparative Example 4 is a catalyst carrying Pt 0.587 g / L and Rh 0.236 g / L, respectively.

実施例１〜実施例８及び比較例１〜比較例４から製造した各触媒を用いて、耐久試験を行った後、NOｘ、HC、COについての浄化率を評価した。 Using each catalyst manufactured from Examples 1 to 8 and Comparative Examples 1 to 4, after performing a durability test, the purification rates for NOx, HC, and CO were evaluated.

[耐久試験方法]
上記各実施例及び各比較例から得られた各触媒を用いて、排気量3500ccのV型エンジンの排気系に片バンクあたり触媒を5個ずつ装着した。そして、国内レギュラーガソリンを使用して、触媒入口温度650℃として30時間運転した。 [Durability test method]
Five catalysts per bank were mounted on the exhaust system of a V-type engine with a displacement of 3500 cc using each catalyst obtained from the above Examples and Comparative Examples. Then, domestic regular gasoline was used and the catalyst was operated at a catalyst inlet temperature of 650 ° C. for 30 hours.

[浄化率の評価]
浄化率は、実施例１〜実施例８及び比較例１〜比較例４の各触媒について、いずれも耐久試験による熱履歴後に評価したものである。 [Evaluation of purification rate]
The purification rate is evaluated after the heat history by the durability test for each of the catalysts of Examples 1 to 8 and Comparative Examples 1 to 4.

耐久試験後における各実施例及び各比較例の触媒を模擬排気ガス流通装置に組み込んだ後、表１に示す組成の模擬排気ガスを流通させて、速度30℃/分で触媒を昇温させながら、NOｘ、HC、COの浄化率が50％となる温度を調べた。

After incorporating the catalysts of each Example and each Comparative Example after the durability test into the simulated exhaust gas circulation device, the simulated exhaust gas having the composition shown in Table 1 was circulated and the temperature of the catalyst was increased at a rate of 30 ° C / min. The temperature at which NOx, HC and CO purification rates were 50% was investigated.

表２に、各触媒について、NOｘ、HC、COの浄化率を評価した結果を示す。また、図２には、実施例１〜実施例８及び比較例１〜比較例４の各触媒について、HCの浄化率が50％となる温度を図示した。

Table 2 shows the results of evaluating the NOx, HC, and CO purification rates for each catalyst. FIG. 2 illustrates the temperatures at which the HC purification rate is 50% for the catalysts of Examples 1 to 8 and Comparative Examples 1 to 4.

表２に示すように、比較例１は、含浸法を用いてPt溶液を含浸させて調製した通常の触媒であり、初期のPt粒径は非常に小さく分散性が良好であったが、TEMにて耐久後のPt粒子を観察したところ、Pt粒子の粒径は20nm〜30nmに拡大していることが判った。この結果、含浸法では耐久試験による熱履歴を受けると、Pt粒子が移動してPt粒子同士間の距離が縮まり、Pt粒子が凝集し易くなったものと考えられる。 As shown in Table 2, Comparative Example 1 is a normal catalyst prepared by impregnating a Pt solution using an impregnation method. The initial Pt particle size was very small and the dispersibility was good. When the Pt particles after endurance were observed, the particle size of the Pt particles was found to be expanded to 20 nm to 30 nm. As a result, in the impregnation method, it is considered that when receiving a heat history by the durability test, the Pt particles move, the distance between the Pt particles is reduced, and the Pt particles are easily aggregated.

また、比較例２の触媒のPt粒子をTEM観察したところ、初期のPt粒子は微粒子表面に付いていたが、耐久後のPt粒子は凝集して粒径が20nm〜30nmに拡大していた。これは、比較例２の触媒に使用した微粒子の粒径が3nmと微小すぎて、比較例１と同様にPt粒子同士の距離が短く、Pt粒子が凝集し易くなったものと考えられる。 Further, when the Pt particles of the catalyst of Comparative Example 2 were observed by TEM, the initial Pt particles were attached to the surface of the fine particles, but the endured Pt particles were aggregated and the particle size was enlarged to 20 nm to 30 nm. This is presumably because the particle diameter of the fine particles used in the catalyst of Comparative Example 2 was too small, 3 nm, and the distance between the Pt particles was short as in Comparative Example 1, and the Pt particles easily aggregated.

さらに、比較例３及び比較例４の初期と耐久後とにおける触媒のPt粒子の粒径には大幅な違いが見られなかったが、初期のPt粒子の粒子径が20nm〜30nm程度と大きく、触媒の性能が劣ることになったものと考えられる。 Furthermore, although there was no significant difference in the particle size of the catalyst Pt particles in the initial period and after the endurance of Comparative Example 3 and Comparative Example 4, the initial Pt particle size was as large as about 20 nm to 30 nm. It is thought that the performance of the catalyst was inferior.

これに対して、実施例１から実施例８までの各触媒では、初期と耐久後とにおけるPt粒子の粒径に大きな変化はみられず、浄化率を評価したところNOｘ、HC、COの各浄化温度が低いことから、高い浄化率を得られることが判明した。 On the other hand, in each catalyst from Example 1 to Example 8, there was no significant change in the particle size of the Pt particles in the initial stage and after the endurance, and the purification rate was evaluated, and each of NOx, HC, and CO was evaluated. It was found that a high purification rate can be obtained because the purification temperature is low.

また、実施例１から実施例８までは、２段階のめっき処理をして調製したPt粒子AからPt粒子GまでのPt粒子を使用したため、表２に示すように、耐久前におけるPt粒子の比表面積を大きくすることができる。これは、前処理として貴金属量を調整し微粒子（アルミナ粒子等）表面の一部にPtのめっき処理をすると、アルミナ粒子の約20％〜30％の面に薄いPtめっき層が形成され、この箇所が種となり、再度めっき処理をすると、Ptめっき上に選択的にPtめっきが形成されて厚みが増し、比表面積の大きいPt被覆粒子を形成することができるからである。 Moreover, since Pt particles from Pt particles A to Pt particles G prepared by performing two-step plating treatment were used in Examples 1 to 8, as shown in Table 2, the Pt particles before durability were used. The specific surface area can be increased. This is because when a precious metal amount is adjusted as a pretreatment and a part of the surface of fine particles (alumina particles, etc.) is plated with Pt, a thin Pt plating layer is formed on the surface of about 20% to 30% of the alumina particles. This is because when the spot becomes a seed and plating is performed again, Pt plating is selectively formed on the Pt plating, the thickness is increased, and Pt-coated particles having a large specific surface area can be formed.

本発明の実施の形態に係る触媒活性粒子を製造する方法であり、めっき処理を用いた製造工程を説明する図である。It is a method for producing catalytically active particles according to an embodiment of the present invention, and is a diagram for explaining a production process using plating treatment. 実施例１〜実施例８及び比較例１〜比較例４の各触媒について、HC浄化率が50％となる温度との関係を示す図である。It is a figure which shows the relationship with the temperature from which HC purification | cleaning rate will be 50% about each catalyst of Example 1- Example 8 and Comparative Example 1- Comparative Example 4. FIG.

符号の説明Explanation of symbols

１…アルミナ粒子,
２…Ptめっき層,
３…Pt貴金属層, 1 ... Alumina particles,
2 ... Pt plating layer,
3 ... Pt precious metal layer,

Claims

基材と、
前記基材上に担持され、かつ、表面の少なくとも一部に一種以上の貴金属から形成される貴金属層を被覆すると共に、粒径が5nm〜100nmである微粒子と、
を含むことを特徴とする排ガス浄化用触媒。 A substrate;
The fine particles having a particle size of 5 nm to 100 nm, which are supported on the base material and coat a noble metal layer formed of one or more noble metals on at least a part of the surface,
An exhaust gas purifying catalyst comprising:

前記貴金属層の厚さは、0.3nm〜3nmであることを特徴とする請求項１記載の排ガス浄化用触媒。 The exhaust gas purifying catalyst according to claim 1, wherein the noble metal layer has a thickness of 0.3 nm to 3 nm.

前記貴金属層は、白金、パラジウム及びロジウムの中から選択される少なくとも一種以上の貴金属から形成されることを特徴とする請求項１又は２記載の排ガス浄化用触媒。 The exhaust gas purifying catalyst according to claim 1 or 2, wherein the noble metal layer is formed of at least one or more kinds of noble metals selected from platinum, palladium, and rhodium.

前記微粒子は、無機化合物から形成されることを特徴とする請求項１記載の排ガス浄化用触媒。 The exhaust gas-purifying catalyst according to claim 1, wherein the fine particles are formed of an inorganic compound.

前記微粒子は、アルミナ、セリア、ジルコニア、アルカリ金属及びアルカリ土類金属の中から選択される少なくとも一種以上の無機化合物から形成されることを特徴とする請求項１記載の排ガス浄化用触媒。 2. The exhaust gas purifying catalyst according to claim 1, wherein the fine particles are formed of at least one inorganic compound selected from alumina, ceria, zirconia, alkali metal and alkaline earth metal.

前記微粒子は、アルミナ、酸化チタン、酸化鉄、酸化亜鉛、酸化セリウム、酸化イットリウム、酸化ケイ素、酸化マンガン、酸化マグネシウム、酸化ジルコニウム、酸化スズ、酸化銅、酸化コバルト、酸化タングステン、酸化モリブデン、チタンシリケート、アルミニウムシリケート、チタン酸バリウム及びこれらの複合化合物の中から選択される少なくとも一種以上の無機化合物から形成されることを特徴とする請求項１記載の排ガス浄化用触媒。 The fine particles are alumina, titanium oxide, iron oxide, zinc oxide, cerium oxide, yttrium oxide, silicon oxide, manganese oxide, magnesium oxide, zirconium oxide, tin oxide, copper oxide, cobalt oxide, tungsten oxide, molybdenum oxide, titanium silicate. The exhaust gas-purifying catalyst according to claim 1, wherein the exhaust gas-purifying catalyst is formed from at least one inorganic compound selected from the group consisting of aluminum silicate, barium titanate, and composite compounds thereof.

前記貴金属層は、無電解めっき法又は化合物分解法を用いて前記微粒子の表面の少なくとも一部に形成されることを特徴とする請求項１乃至３のいずれか１項に記載の排ガス浄化用触媒。 The exhaust gas purifying catalyst according to any one of claims 1 to 3, wherein the noble metal layer is formed on at least a part of the surface of the fine particles using an electroless plating method or a compound decomposition method. .

無機化合物から形成される微粒子の表面の一部に、めっき法又は化合物分解法を用いて一種以上の貴金属から形成される貴金属層を被覆して触媒活性成分とする触媒活性成分調製工程と、
前記触媒活性成分を基材上に担持する担持工程と、
を含むことを特徴とする排ガス浄化用触媒の調製方法。 A catalytic active component preparation step in which a part of the surface of the fine particles formed from the inorganic compound is coated with a noble metal layer formed from one or more noble metals using a plating method or a compound decomposition method to form a catalytic active component;
A supporting step of supporting the catalytically active component on a substrate;
A method for preparing an exhaust gas purifying catalyst, comprising:

前記触媒活性成分調整工程における前記貴金属層を形成する貴金属の比表面積を16m²/g〜175m²/gとすることを特徴とする請求項８記載の排ガス浄化用触媒の調製方法。 Preparation process of claim 8, wherein the exhaust gas purifying catalyst, characterized in that the specific surface area of the noble metal forming the noble metal layer in the catalytically active component adjusting step and 16m ^² / g~175m ² / g.

前記めっき法は、無電解めっき法であり、めっき液中の貴金属量に応じて、前記微粒子上に被覆する貴金属層の被覆率及び厚さを制御し、前記化合物分解法は、前記微粒子に塗布する貴金属化合物の液量及び濃度に応じて、微粒子上に被覆した貴金属層の被覆率及び厚さを制御することを特徴とする請求項８又は９記載の排ガス浄化用触媒の調製方法。 The plating method is an electroless plating method, and the coverage and thickness of the noble metal layer coated on the fine particles are controlled according to the amount of noble metal in the plating solution, and the compound decomposition method is applied to the fine particles. The method for preparing an exhaust gas purifying catalyst according to claim 8 or 9, wherein the coverage and thickness of the noble metal layer coated on the fine particles are controlled in accordance with the liquid amount and concentration of the noble metal compound.